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Biomedical subjects

Prem Kumar

Publications and source records attributed to Prem Kumar.

27 records · Page 2Linked to original sources

High-speed data encryption over 25 km of fiber by two-mode coherent-state quantum cryptography.

We demonstrate high-speed (250 Mbps) data encryption over 25 km of telecommunication fiber by use of coherent states. For the parameter values used in the experiment, the demonstration is secure against individual ciphertext-only eavesdropping attacks near the transmitter with ideal detection equipment. Whereas other quantum-cryptographic schemes require the use of fragile quantum states and ultrasensitive detection equipment, our protocol is loss tolerant, uses off-the-shelf components, and is optically amplifiable.

Journal Article↗

Secure communication using mesoscopic coherent states.

We demonstrate theoretically and experimentally that secure communication using intermediate-energy (mesoscopic) coherent states is possible. Our scheme is different from previous quantum cryptographic schemes in that a short secret key is explicitly used and in which quantum noise hides both the bit and the key. This encryption scheme allows optical amplification. New avenues are open to secure communications at high speeds in fiber-optic or free-space channels.

Journal Article↗

Measurement of the photon statistics and the noise figure of a fiber-optic parametric amplifier.

We report measurement of the noise statistics of spontaneous parametric fluorescence in a fiber parametric amplifier with single-mode, single-photon resolution. We employ optical homodyne tomography for this purpose, which also provides a self-calibrating measurement of the noise figure of the amplifier. The measured photon statistics agree with quantum-mechanical predictions, and the amplifier's noise figure is found to be almost quantum limited.

Journal Article↗

A preliminary evaluation of the efficacy and safety of Cogent db (an ayurvedic drug) in the glycemic control of patients with type 2-diabetes.

OBJECTIVES AND STUDY DESIGN: A nonrandomized, non-placebo-controlled clinical trial to evaluate the efficacy of Cogent db (an herbal preparation; Cybele Herbal Laboratories [PVT] Ltd. Kochi, Kerala State, India) as an adjuvant in the treatment of patients with type 2 diabetes was carried out during a 3-month period. SETTINGS/LOCATION: This study was conducted in two major peripheral clinics of Kuala Lumpur in the Klang Valley, Malaysia. SUBJECTS: A total of 39 Cogent db-treated cases and 40 age-matched controls were recruited for this preliminary study. Nineteen (19) subjects (10 and 9 from control and treatment groups, respectively) dropped out of the study leaving a total of 60 subjects (30 each for control and treatment groups) who completed the study. INTERVENTIONS: All subjects in the treatment group were given Cogent db (2 tablets three times daily after each meal) in addition to the regular allopathic drugs (Daonil, [Aventis Farma, SA Petaling Jaya, Selangor State, Malaysia] and Diamicron [Sevier, Bangkok, Thailand], with or without Metformin [Upha Corporation, Bangi, Selangor State, India]) that they took in common with the control group. OUTCOME MEASURES: Thirty-two (32) clinical variables were investigated, including liver enzymes, kidney function tests, hematologic parameters, blood glucose, insulin, and C-peptide assays. RESULTS: At the end of 3 months it was found that there was a significant decrease in the levels of fasting and postprandial blood glucose, cholesterol, triglycerides, glycated hemoglobin (Hb A(1C)) and fasting insulin in the treatment group compared to the controls. Cogent db did not alter the liver function tests, hematologic parameters, or the kidney function tests. CONCLUSIONS: These results concur with earlier animal studies that indicate that Cogent db is safe, reliable, tolerable, and efficacious in the control of type 2 diabetes mellitus.

Adult↗

Rectal schwannoma.

Solitary schwannomas constitute only 2%-6% of stromal tumors of the gastrointestinal tract; the stomach is the preferred site of involvement. We report a 35-year-old woman who presented with difficulty in defecation. A mass on the posterior wall of the rectum was excised. Histologically, the lesion was a schwannoma, with S-100 proteins positivity and glial fibrillary acidic protein immunoreactivity. The patient is asymptomatic two years later.

Adult↗

Hereditary angioedema: a rare but potentially lethal disease.

Hereditary angioedema, although uncommon, should be considered in the differential diagnosis of all patients with facial edema. In this article, we present a case of hereditary angioedema and discuss the presentation, diagnosis, and management of the disease.

Adolescent↗